Portable blower

ABSTRACT

A brushless motor is incorporated in one of divided constituent members of a motor casing which is disassembled, and then, the divided constituent members of the motor casing which is disassembled are connected to each other into the motor casing assembled with machine screws screwed into machine screw holes. As this occurs, when a wiring of the brushless motor is held by a first stationary blade portion and a second stationary blade portion, the wiring is allowed to lead to an outside of an outer cylindrical portion through a gap defined between the first stationary blade portion and the second stationary blade portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from Japanese Patent Application No.2012-181937 filed on Aug. 20, 2012, the entire subject-matter of whichis incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a portable blower which is configuredto blow off dust or the like for cleaning.

BACKGROUND

In a cordless portable blower, a motor built in the main body thereof isdriven using the power of a battery (e.g., a battery pack) to rotate afan to thereby generate an air current, and the air current is injectedthrough a nozzle for cleaning (see, for example, JP-T-3-501814). Anoperator carries out a cleaning operation while gripping the handleportion of the blower. Generally, in order to blow off dust or the likeon the ground, while holding the blower main body with the nozzledirected obliquely downward and forward, the operator swings the mainbody right and left to thereby blow off the dust or the like. Here, acentrifugal fan or an axial flow fan is used in the blower.

SUMMARY

In a related-art blower using an axial flow fan, there is provided acasing for a motor (a motor casing) separately from a molded member onwhich stationary blades are formed, which increases the number ofconstituent components involved, eventually leading to an increase incost. Even when attempting to incorporate the motor inside the moldedmember on which the stationary blades are formed to cope with theproblem above, the incorporation of the motor in the interior of theintegrally molded member involves a complicated assemblage and hence hasbeen difficult to be implemented.

In addition, in blowers, to meet an increasing demand for smallerblowers, it is demanded to reduce a total axial length of a motor and afan.

Further, in blowers, in the event that through holes for assemblingmotor casing members together remain open while facing an air flow path,there is caused a problem that the assembling through holes affect anair flow passing through the air flow path.

Therefore, one illustrative aspect of the invention provides a blowerincluding a motor casing having a stationary blade portion formedintegrally thereon and holding a motor thereinside.

Another illustrative aspect of the invention provides a blower which canreduce a total axial length of a motor and a fan.

Still another illustrative aspect of the invention provides a blowerwhich can reduce the degree of influence of through holes for assemblingmotor casing members together on an air flow passing through an air flowpath.

According to a first aspect of the invention, there is provided aportable blower comprising: a motor; and a motor casing configured tosupport the motor, wherein the motor casing comprises: an outercylindrical portion; an inner cylindrical portion, wherein the motor ispositioned in an inside of the inner cylindrical portion; and stationaryblade portions which are provided so as to bridge between the outercylindrical portion and the inner cylindrical portion, and wherein themotor casing is made up by integrally combining a first dividedconstituent member and a second divided constituent member.

According to a second aspect of the invention, there is provided aportable blower comprising: a motor; a fan configured to be rotated bythe motor; and a motor casing configured to support the motor, whereinthe motor casing comprises a bearing hold portion configured to hold abearing that is configured to support a rear end portion of an outputshaft of the motor, and wherein the fan comprises: a dome portion whichcovers the bearing holding portion; and moving blade portions which areprovided on the dome portion, and wherein the moving blade portions andthe bearing overlap in an axial direction.

According to a third aspect of the invention, there is provided aportable blower comprising: a main body housing; a motor casing which isfixed to the main body housing; and a motor which is supported on themotor casing, wherein the motor casing comprises: an outer cylindricalportion; and an inner cylindrical portion, wherein the motor ispositioned in an inside of the inner cylindrical portion, and whereinthe motor casing is made up of divided constituent members, wherein anassembling through hole is provided in the outer cylindrical portion,and wherein a projecting portion for filling the assembling through holeis provided on an inner surface of the main body housing.

Incidentally, arbitrary combinations of the above-described constituentelements and changes in representation of the invention with respect tomethod and system are also effective as embodiments of the invention.

According to the first aspect of the invention, it is possible torealize the portable blower including the motor casing which has thestationary blade portions provided integrally thereon and holding themotor thereinside.

According to the second aspect of the invention, it is possible toprovide the blower which can reduce the total axial length of the motorand the fan.

According to the third aspect of the invention, it is possible torealize the blower which can reduce the influence of the assemblingthrough hole in the motor casing on the air flow passing through the airflow path.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side section view of a cordless portable blower according toan exemplary embodiment of the invention;

FIG. 2 is a perspective view of the cordless portable blower, with oneof the portions of a bisected main body housing removed therefrom;

FIG. 3 is a rearward perspective view of the cordless portable blower;

FIG. 4 is a rearward perspective view of the cordless portable blower,with a cover removed therefrom;

FIG. 5 is a rearward perspective view of the cordless portable blower,with the main body housing disassembled;

FIG. 6 is a first forward perspective view of a motor casing of thecordless portable blower;

FIG. 7 is perspective views of the motor casing and its internalstructure, with the motor casing disassembled;

FIG. 8 is a second forward perspective view of the motor casing;

FIG. 9 is a third forward perspective view of the motor casing;

FIG. 10 is a rearward perspective view of the motor casing and itsinternal structure;

FIG. 11 is a rearward perspective view of the motor casing and itsinternal structure, when a fan is removed and the motor casing is cut inits longitudinal middle position to thereby provide a section thereof;and

FIG. 12 is a rearward perspective view of the motor casing and itsinternal structure, with the fan removed.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments of the invention will be describedwith reference to the accompanying drawings. Here, the same orequivalent composing elements, members and the like shown in therespective drawings are given the same designations and the duplicateddescription thereof is omitted properly. Also, the exemplary embodimentdoes not limit the invention but illustrates an example of theinvention, and thus characteristics and their combinations described inthe exemplary embodiment are not always the essential matter of theinvention.

FIG. 1 is a side section view of a cordless portable blower according tothe exemplary embodiment of the invention. FIG. 2 is a perspective viewof the cordless portable blower, with one of the portions of a bisectedmain body housing 3 removed therefrom. FIG. 3 is a rearward perspectiveview of the cordless portable blower. FIG. 4 is a rearward perspectiveview of the cordless portable blower, with a cover 8 a removedtherefrom. FIG. 5 is a rearward perspective view of the cordlessportable blower, with the main body housing 3 disassembled. FIG. 6 is afirst forward perspective view of a motor casing 11 of the cordlessportable blower. FIG. 7 is perspective views of the motor casing 11 andits internal structure, with the motor casing 11 disassembled. FIG. 8 isa second forward perspective view of the motor casing 11. FIG. 9 is athird forward perspective view of the motor casing 11. FIG. 10 is arearward perspective view of the motor casing 11 and its internalstructure. FIG. 11 is a rearward perspective view of the motor casing 11and its internal structure, when a fan 2 is removed and the motor casing11 is cut in its longitudinal middle position to thereby provide asection thereof. FIG. 12 is a rearward perspective view of the motorcasing 11 and its internal structure, with the fan 2 removed therefrom.

As shown in FIG. 1, the cordless portable blower includes, for example,a brushless motor 1 and a fan 2 within the main body housing 3 made ofresin, for example. A trigger switch 5 (speed control trigger switch) isprovided on the forefinger side of the handle portion 3 a (grip portion)of the main body housing 3, while a tactile switch 6 (operation button)is provided on the thumb side thereof. The main body housing 3 includesa battery mounting portion 3 b behind the handle portion 3 a. A batterypack 7 serving as a battery is removably mounted on the battery mountingportion 3 b. The main body housing 3 has an air inlet 8 in its rear end(in FIG. 1, left end), while a cylindrical air guide passage member 9made of resin, for example, is mounted on its front end (in FIG. 1,right end). A cover 8 a having a large number of mesh-pattern openingsis removably mounted on and fixed to the air inlet 8. A nozzle 10 ismounted on an air outlet 9 a formed in the front end of the air guidepassage member 9. When an operator pulls the trigger switch 5, power issupplied from the battery pack 7 to the brushless motor 1 to rotate thebrushless motor 1. Thus, for example, the fan 2 rotatable integrallywith the brushless motor 1 generates an air current, whereby air suckedfrom the air inlet 8 is blown out from the air outlet 9 a to the outsidethrough the nozzle 10 e. The driving control of the brushless motor 1 iswell known and thus the description thereof is omitted here.

As can be seen from FIGS. 3 and 4, the battery mounting portion 3 bprojects convexly into an air passage (projects convexly into the airinlet 8). A bottom surface section 31 and side surface sections 32, 33of the battery mounting portion 3 b configure part of the inner surfaceof the air passage. Also, the battery mounting portion 3 b holds thebattery pack 7 in such manner that the center of gravity of the batterypack 7 exists at an attitude as close to the handle portion 3 a aspossible. Specifically, the battery mounting portion 3 b holds thebattery pack 7 such that the greatest surface of the battery pack 7having a substantially cuboid shape faces the handle portion 3 a. Also,the battery mounting portion 3 b holds the battery pack 7 such that thelongitudinal direction of the battery pack 7 faces the air passage.

The fan 2 includes a dome portion 16 and a moving blade 17. The domeportion 16 is configured to not only prevent dust or the like fromentering the brushless motor 1 but also arrange the air current. Themoving blade 17 is provided on and projected outwardly from the base-endside outer peripheral surface of the dome portion 16. The moving blade17 includes a predetermined number of (e.g., twelve) moving blades atregular angular intervals around the shaft of the fan 2. The fan 2 isfixed to the rear end portion of the output shaft 43 of the brushlessmotor 1 by, for example, a nut and can be rotated integrally with theoutput shaft 43. The dome portion 16 covers a rear bearing hold portion15, while the moving blade 17 overlaps with a rear bearing 13 in theaxial portion thereof This can reduce the total of the axial-directionlengths of the brushless motor 1 and fan 2.

As shown in FIG. 2, the main body housing 3 is bisected right and left.A motor casing 11, for example, made of resin is mounted on and fixed tothe inside of the main body housing 3 using screwing holes 23 (byscrewing). The motor casing 11 is also bisected right and left (refer toFIG. 7 as well), while the right and left portions of the bisected motorcasing 11 are connected into an integral body by screwing the screwingholes 23. Here, the screws for fixing the motor casing 11 are used incommon with some of the screws for connecting together the right andleft portions of the main body housing 3. As shown in FIGS. 6 to 12, themotor casing 11 includes an outer cylindrical portion 34, an innercylindrical portion 35, a stationary blade 36, an air current arrangingcone 18, a front bearing hold portion 14 (refer to FIG. 7) and a rearbearing hold portion 15 (refer to FIG. 12).

The outer cylindrical portion 34 extends along the inner surface of themain body housing 3. The inner cylindrical portion 35 holds the statorcore 41 of the brushless motor 1. Specifically, as shown in FIG. 11, theinner peripheral surface of the inner cylindrical portion 35 is engagedwith the outer peripheral surface of the stator core 41 of the brushlessmotor 1, for example, in a concavo-convex manner. The stationary blades36 are disposed to connect together the outer and inner cylindricalportions 34 and 35, and are arranged obliquely relative to the airpassage. The stationary blade 36 includes a predetermined number of(e.g., seven) blades which are arranged at irregular angle intervalsaround the shaft of the fan 2. To arrange them at irregular angleintervals is to prevent noises from increasing due to resonance. Also,the number of the stationary blades 36 is set such that, in view of theabove-mentioned number of the moving blades 17 of the fan 2, one of themis not an integral multiple of the other. This is also to prevent noisesfrom increasing due to resonance

As can be seen clearly from FIG. 11, one of the stationary blades 36 isproduced by butting a first stationary blade portion 36A formed in oneof the portions of the bisected motor casing 11 against a secondstationary blade portion 36B formed in the other portion. And, thewiring 40 (refer to FIG. 7) of the brushless motor 1 is guided to theoutside of the outer cylindrical portion 34 through a clearance 39between the first and second stationary blade portions 36A and 36B.Through the wiring 40, the battery pack 7 and control circuit existingoutside the outer cylindrical portion 34 (outside the air passage) areelectrically connected to the brushless motor 1 and switching board 44existing inside the outer cylindrical portion 34 (inside the airpassage). Since the wiring 40 is guided from the inside of the airpassage to the outside thereof through the clearance 39 between thefirst and second stationary blade portions 36A and 36B, the influence(such as the disturbance of the air current)of the wiring 40 on the aircurrent of the air passage can be reduced or eliminated. Such wiring 40arrangement can also reduce or eliminate a risk of the wiring 40 beingcut by the air current of the air passage or by dust and the like suckedtherein.

As shown in FIG. 7, inside the inner cylindrical portion 35, theswitching board 44 with a predetermined number of switching elements 20(FETs or the like) mounted thereon is fixed through an insulator 42 (aninsulating member) to the stator core 41 of the brushless motor 1, forexample, by screwing. In order to enhance the heat radiating property ofthe switching elements 20, cooling holes 38 (penetration holes)communicating with the air passage are formed in the inner cylindricalportion 35 (refer to FIGS. 8, 9 and the like). This can prevent heatgenerated by the switching elements 20 from staying inside the innercylindrical portion 35 and air current arranging cone 18, whereby theheat radiating property of the switching elements 20 can be enhanced.The cooling holes 38 are formed at positions which, when viewed from theincoming side of the air passage, exist behind the stationary blade 36.

The air current arranging cone 18 extends forward continuously from thefront end of the inner cylindrical portion 35. As shown in FIG. 7, theair current arranging cone 18 includes screwing holes 24 to 26 formed inits side surface. The screwing holes 24 to 26 are screwed to screwingbosses 45 to 47 (respectively having a female screw hole in theirleading ends) projected from the inner surface of the air currentarranging cone 18, thereby ensuring the integral connection of the rightand left portions of the bisected cone 18. A spanner insertion hole 37(slit) is also formed in the side surface of the air current arrangingcone 18. In assembling, a rectangular column portion 19 (portion that isprojected forward from the front bearing 12) of the front end of theoutput shaft 43 of the brushless motor 1 can be fixed against rotationusing a tool such as a spanner or the like through the spanner insertionhole 37, whereby the fan 2 can be easily mounted onto the rear end ofthe output shaft 43.

The front bearing hold portion 14, as shown in FIG. 7, has asubstantially U-shaped section and extends from the inner surface of theair current arranging cone 18 to hold the front bearing 12. Although notshown, another front bearing hold portion 14 extends symmetrically alsofrom the inner surface of the air current arranging cone 18 on this sideto hold the front bearing 12. The front bearing 12 supports the frontend of the output shaft 43 of the brushless motor 1 rotatably. As shownin FIG. 12, the rear bearing hold portion 15 extends from the rear endof the inner cylindrical portion 35 to fix and hold the rear bearing 13.The rear bearing 13 supports the rear end of the output shaft 43 of thebrushless motor 1 rotatably. The rear bearing hold portion 15 includesscrewing holes 27, 28, and to screw the screwing holes 27, 28 ensuresthe integral connection of the right and left portions of the bisectedrear bearing hold portion 15. Here, in screwing, a tool such as a driveror the like can be inserted through a predetermined number of (forexample, two) driver insertion holes 21 formed in the outer cylindricalportion 34, whereby the efficiency of the screwing operation can beenhanced. The driver insertion holes 21, as shown in FIG. 5, can befilled with hole filling projections 22 provided on the inner surface ofthe main body housing 3 (they are fitted in such a manner that noclearance can be produced between them as much as possible). The leadingend face of the hole filling projection 22 may preferably be flush withthe inner peripheral surface of the outer cylindrical portion 34.Provision of the hole filling projections 22 can reduce or eliminate theill influences of the driver insertion holes 21 on the air passage.

As shown in FIG. 2, the air guide passage member 9 includes apredetermined number of (for example, four) projections 9 b on its outerperipheral surface. When the projections 9 b are engaged with the samenumber of recesses 3 c formed in the inner surface of the main bodyhousing 3, the air guide passage member 9 can be fixed to the main bodyhousing 3. The rear end edge of the air guide passage member 9 maypreferably be contacted with the front end edge of the outer cylindricalportion 34 of the motor casing 11 with no clearance between them.

Now, description is given simply of an example of the flow of theassembling operation of the cordless portable blower according to thepresent exemplary embodiment.

Firstly, after the brushless motor 1 is incorporated into one of theportions of the bisected motor casing 11 in such a manner as shown inFIG. 7, the portions of the motor casing 11 are connected together intoan integral body by screwing the screwing holes 24 to 26 (refer to FIG.7) and screwing holes 27, 28 (refer to FIG. 12). In this case, thewiring 40 of the brushless motor 1 is sandwiched between the first andsecond stationary blade portions 36A and 36B, whereby the wiring 40 isguided from the clearance 39 between the first and second stationaryblade portions 36A and 36B (refer to FIG. 11 and the like) to theoutside of the outer cylindrical portion 34. Here, as described above,when screwing the screwing holes 27, 28, the driver insertion hole 21 ofthe outer cylindrical portion 34 can be used. Then, the fan 2 is mountedonto the rear end of the output shaft 43 of the brushless motor 1. Inthis case, in order to stop the rotation of the output shaft 43, a toolsuch as a spanner or the like is inserted from the spanner insertionhole 37 (refer to FIG. 6 and the like) to thereby lock the rectangularcolumn portion 19 of the front end of the output shaft 43. Then, theprojections 9 b of the air guide passage member 9 are engaged with therecesses 3 c of one of the portions of the bisected main body housing 3,the motor casing 11 is positioned in one portion of the bisected mainbody housing 3, and the other portion of the main body housing 3 is thenput on one portion from above. In this state, by screwing the screwingholes 23, the portions of the motor casing 11 are fixed to each otherand further, by screwing the remaining screwing holes, they areconnected together into an integral body, the cover 8 a is mounted andfixed to the air inlet 8 of the rear end of the main body housing 3, andthe nozzle 10 is mounted onto the front end of the air guide passagemember 9.

The exemplary embodiments can provide the following advantages.

(1) The battery mounting portion 3 b projects convexly into the airpassage and the outer surfaces of the bottom surface section 31 and sidesurface sections 32, 33 of the battery mounting portion 3 b configurepart of the inner surface of the air passage. Therefore, the batterypack 7 can provide excellent heat radiating property. This can preventthe battery pack 7 against overheating and thus can advantageouslyextend the life of the battery pack 7. Also, when the high temperatureprotection function of the battery pack 7 is provided, the frequentoperation of the protection function can be prevented to thereby enhancethe blower operation efficiency.

(2) The battery pack mounting portion 3 b holds the battery pack 7 insuch a manner that the center of gravity of the battery pack 7 exists atan attitude as close to the handle portion 3 a as possible. Therefore,while in operation, especially when swinging the blower main body rightand left, the influence of the moment of inertia of the battery pack 7can be reduced to thereby enhance the operation performance of theblower. Also, when the weight of the battery pack 7 is caused to varydue to the varied capacity thereof, or when mounting, instead of thebattery pack 7, an adapter provided on the leading end of a cableextended from an external power supply such as a back-carrying powersupply (the adapter is similar in shape to the battery pack but islighter in weight), the influence of the battery pack 7 or adapter onthe blower main body can be reduced, whereby the operation performanceof the blower can be enhanced in this respect as well.

(3) The battery pack 7 projects convexly into the air inlet 8.Therefore, the battery pack 7 provides a sound insulation effect (sincethe battery pack 7 is heavy, the battery pack 7 serves effectively as asound insulation wall), thereby being able to enhance the tranquility ofthe blower.

(4) The inner cylindrical portion 35 includes the cooling hole 38communicating with the air passage. Therefore, the switching element 20provided inside the inner cylindrical portion 35 is enhanced in its heatradiating properties.

(5) The motor casing 11 is bisected and the wiring 40 of the brushlessmotor 1 is guided from inside the inner cylindrical portion 35 (frominside the air passage) to outside the outer cylindrical portion 34 (tooutside the air passage) through the clearance 39 of the bisectedstationary blade 36 (the clearance 39 between the first and secondstationary blade portions 36A and 36B shown in FIG. 7 and the like).Therefore, the influence of the wiring 40 on the air current of the airpassage (such as the disturbance of the air current) can be reduced oreliminated. This can also reduce or eliminate a risk of the wiring 40being cut by the air current of the air passage or by dust or the likesucked therein.

(6) When screwing the screwing holes 27 and 28, a tool such as a drivercan be inserted through the driver insertion holes 21 formed in theouter cylindrical portion 34, whereby the assembling operationefficiency of the blower is enhanced. On the other hand, afterassembled, the hole filling projections 22 provided on the inner surfaceof the main body housing 3 fill the driver insertion holes 21. This canreduce or eliminate the ill influence of the driver insertion holes 21on the air passage. Also, the hole filling projections 22 and driverinsertion holes 21 are engaged with each other and thus they arepositioned when assembling the blower. This can further enhance theefficiency of the blower assembling operation.

(7) The spanner insertion hole 37 is formed in the side surface of theair current arranging cone 18. Therefore, when assembling the blower,the rectangular column portion 19 of the front end of the output shaft43 of the brushless motor 1 can be fixed against rotation by a tool suchas a spanner or the like through the spanner insertion hole 37, therebybeing able to enhance the efficiency of an operation to mount the fan 2onto the rear end of the output shaft 43 using a nut or the like.

(8) The rear bearing 13 and the moving blade 17 of the fan 2 overlapwith each other in their axial-direction positions. Therefore, the totalof the axial-direction lengths of the brushless motor 1 and fan 2 can bereduced.

(9) The stationary blades 36 are arranged at irregular angle intervalsaround the fan shaft. Therefore, an increase in noise due to resonancecan be prevented to thereby enhance the tranquility of the blower. Thenumber of the stationary blades 36 and the number of the moving blades17 of the fan 2 are set such that one will not be an integer multiple ofthe other, whereby an increase in noise due to resonance can beprevented and thus the tranquility of the blower can be enhanced in thisrespect as well.

Although the invention has been described with reference to the aboveexemplary embodiments, it is obvious to persons skilled in the art thatthe respective composing elements and the respective treating process ofthe exemplary embodiment can be changed variously without departing fromthe scope of the appended patent claims.

What is claimed is:
 1. A portable blower comprising: a motor; and amotor casing configured to support the motor, wherein the motor casingcomprises: an outer cylindrical portion; an inner cylindrical portion,wherein the motor is positioned in an inside of the inner cylindricalportion; and stationary blade portions which are provided so as tobridge between the outer cylindrical portion and the inner cylindricalportion, and wherein the motor casing is made up by integrally combininga first divided constituent member and a second divided constituentmember.
 2. The portable blower according to claim 1, wherein at leastone of the stationary blade portions comprises: a first stationary bladeportion which is provided on the first divided constituent member of themotor casing; and a second stationary blade portion which is provided onthe second divided constituent member, and wherein a wiring configuredto energize the motor leads from an inside of the inner cylindricalportion to an outside of the outer cylindrical portion through aclearance between the first stationary blade portion and the secondstationary blade portion.
 3. A portable blower comprising: a motor; afan configured to be rotated by the motor; and a motor casing configuredto support the motor, wherein the motor casing comprises a bearing holdportion configured to hold a bearing that is configured to support arear end portion of an output shaft of the motor, and wherein the fancomprises: a dome portion which covers the bearing holding portion; andmoving blade portions which are provided on the dome portion, andwherein the moving blade portions and the bearing overlap in an axialdirection.
 4. The portable blower according to claim 3, wherein themotor casing comprises an air current arranging cone at a front side ofthe motor, wherein a through hole is provided in a side surface of theair current arranging cone, the through hole being configured to allow atool to pass therethrough to lock a front end portion of the outputshaft when attaching the fan to the rear end portion of the output shaftof the motor.
 5. A portable blower comprising: a main body housing; amotor casing which is fixed to the main body housing; and a motor whichis supported on the motor casing, wherein the motor casing comprises: anouter cylindrical portion; and an inner cylindrical portion, wherein themotor is positioned in an inside of the inner cylindrical portion, andwherein the motor casing is made up of divided constituent members,wherein an assembling through hole is provided in the outer cylindricalportion, and wherein a projecting portion for filling the assemblingthrough hole is provided on an inner surface of the main body housing.6. The portable blower according to claim 5, wherein the assemblingthrough hole is configured to pass a tool therethrough when connectingone of the divided constituent members to the other.